Telephone call-bell.



No. 68|,744. Patented Sept. 3. |901.

. c. E. scmsnen.

TELEPHONE CALL BELL.

Application iiled Jau. 20, 1900.)

(No Modell.l

NiTn STATES PATENT rricn.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE CALL-BELL.

SPECIFICATION forming part of Letters Patent No. 681,744, dated September 3, 1901.

Application filed January 20, 1900. Serial No. 2,109 (N0 model.)

To all whom it may concern.-

Beit known that I, CHARLES E. SGRTBNER, `a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone Call-Bells, (Case No. 483,) of which the following is a full, clear, concise, and exact description.

This invention concerns call-bells for substations of telephone-lines, particularly of the class known as extension-lines, which have two or more substations and which enter a central oiice, the lines being adapted for signaling and communicating between the substations as well as between either substation and the central office. The substations of such lines are commonly provided with batteries for ringing the bells at the other stations, while the central office is furnished with a generator of alternating calling-current. My improved bell is adapted for operation either by a continuous current applied without interruption to the line or by -an interrupted or alternating current.

The invention consists in the combination, with a polarized bell having a centrally-pivoted armature, of two windings on the electromagnet of the bell and switch-contacts carried by the pivoted armature of the bell controlling the circuit through one of the.

windings, the windings being connected in the circuit differentially with respect to each other and that which is normally open-cirlcuited having azgreater number of amperetur-ns than the other. The armature of the bell should preferably be given a light bias by means of a spring tending to draw it normally to one side to break the circuit through 'the greater winding.

My improved bell is illustrated in the drawing herewith, which shows it diagrammatically connected in the circuit of an extensionline with means for applying either alternating or continuous current to the line for operating the bell.

The bell consists, essentially, of the electromagnet o, with two magnet-spools a' and c2, the centrally-pivoted armature h having its ends lying before the poles of the magnetcores, the permanent polarizing-magnet c, connected at one end with the yoke of the electromagnet and having its other pole presented to the armature near its center, the tongue b', carried by the armature, and gongs d, between which the tongue vibrates. These parts are substantially like those of the bells well known in the art of telephony and described in Patent No. 210,886 to T. A. Vatson, dated December 17, 1878.

The electromagnet c 032 has two windings. These two windings are connected in circuits 1 and 2, respectively, which are multiple branches of the circuit to the bell, the connections of each winding with the circuit being the reverse of those of the other, so that the windings act differentially upon the core; but the winding in circuit 2 has a greater number of ampere-turns--for example, fifty per cent. more-than the winding in circuit l.

The armature b carries a movable contact b2, which is adapted to be brought against a fixed contact-stud hgwhen the armature is in one position, and the armature is acted upon by a light spring b4, which tends to draw it normally into its other position. The conductor 2 through the bell includes the switchcontacts b2 b3, and thus the path through it is normally broken.

The multiple branches l and 2 of the bell are connected in a bridge 3 of the line-circuit 4 5, which extends from the station A, where the bell is assumed to be located, to a central station B and to another substation C. The line is adapted for the automatic operation of a call-signal in the central office and is furnished there with a bridge closed in the terminal spring-jack of the line, including a batteryf and a visible signal g. To break the circuit through the bell while the line is not in use, a condenser h is interposed in the line conductor 5. The telephones z' are connected in a bridge of the line which is controlled by the telephone-switch la, which thus completes the circuit of the battery fwhen the telephone is taken for use. Means for ringing the bell at the station A is indicated at the central ofce B as a plug Z for insertion in the springjack, the line-contacts of which may be connected, by means of a key m, with the poles of a generator n of alternating calling-current. The substation A is called from the substation C by means of a key o, normally IOO open, which is arranged to closea circuit bf 1 acting source of current at theV substation C.. When the alternating current is applied toV the line, it finds circuit through the condenser h to the bell, where it iinds a closed path through the Iconductor 1, including one of the windings of the electromagnet of the bell. current of suitable direction magnetizes the coresof the electromagnet in proper direction with reference to the permanent polarity of the armature to throw the armature out of its position of rest, thus causing the tongue b to strike one of the gongs CZ. In this movement of the armature the circuit 2 through the bell is closed at the contacts b2 b3, and the path thus closed diverts current from the path l, which, the winding in path 2 being more powerful, tends to reverse the polarity of the magnet, and thus to throw the armature back to its iirst position. The time required for this action depends upon the natural period of vibration of the bell, to which, as usual, the source of alternating current is adapted. Hence the reversal of polarity of the calling-generator fn occurs during the return of the armature to its initial position, and the winding in conductor l becomes effective in maintaining the reversed polarity of the electromagnet and driving the armature to its initial position. Thus a strong blovx7 is struck upon the other gong in the return of the armature independently of the strength of the spring b4. The action is in effect that of an ordinary polarized bell when actuated by an alternating current of suitable period. When in ringing the bell from the substation C the battery lo is applied to the line by depressing key o, this battery finds circuit through the winding 1, as before, and being adapted in polarity for the operation of the bell it magnetizes the core in proper direction to bring the contact b2 against its anvil b3, and thus to reverse the polarity of the electromagnet The first pulsation of the alternating and -eEect the return of the armature. The armature is thus vthrown into rapid vibration and the bell is rung.

I claim as newand desire to secure by Letters Patent- 1. In combination in a polarized electric bell two differential windings, switch-con tacts carried by the armature of the bell con trolling the continuity of one of said windings, the last-'mentioned winding having a greater number of ampereturns than the other; whereby the bell may be rung with either a continuous or au alternating current.

2. Incombination in a bell, an electromagnet having two windings differential with respect to each other, a centrally-pivot'ed arl mature, a tongue carried thereby and gongs,

a permanent magnet for polarizing the electromagnet and armature,switch-contacts controlled by the armature to be closed when the armature is in one position, means for maintaining the armature normally in its opposite position, and a circuit containing the said two windings in multiple branches, one

of said branches being controlled by the said switch-contacts, as described.

3. In combination an electromagnet with two windings, one having more turns than the other, a centrally-pivoted armature for the magnet, and a permanent magnet for magnetizing the cores of the electromagnet with the same polarity, a tongue carried by the armature, and gongs, a source of alternat= ing and a source of continuous current, and means for applying said sources in the same circuit,said circuit being connected with both windings of the electromagnet, and switchcontacts controlled by the armature adapted to close the circuit through the winding of the greater number of turns when the magnet is excited by a current in the other winding; whereby the bell may be rung by either alternating or pulsating currents, as described.

In witness whereof I hereunto subscribe my name this 22d day of December, A. D. 1899.

CHARLES E. SCRIBNER. Witnesses:

ELLA EDLER, FLORENCE E. SUMMERS. 

